DE102010039653A1 - Method for operating range extender in electric vehicle e.g. electric car, involves activating range extender of vehicle in respective route section based on power requirement of electric vehicle with respect to travel route - Google Patents

Abstract

The method involves estimating power requirement of electric vehicle with respect to a travel route by analyzing route sections of the travel route. The information of the route sections is obtained by accessing navigation equipment (3) in the electric vehicle. The range extender (2) of the electric vehicle is activated in respective route section based on the estimated power requirement of the electric vehicle. An independent claim is included for controller for range extender.

Description

The invention relates to a method for operating a range extender in an electric vehicle, in particular electric car, with an electric traction storage.

Electric vehicles according to the invention are powered by electrical energy via an electric machine vehicles with an electric traction storage (for example, lithium-ion battery), the traction storage can be charged via an on-board power supply externally with electrical energy. Electric vehicles within the meaning of the invention therefore also include so-called plug-in hybrid vehicles with power connection for charging the traction storage, but no hybrid vehicles without power supply for charging the traction storage.

A range extender in an electric vehicle makes it possible to recharge the electric traction storage (electrical energy storage, for example rechargeable battery or condenser) used primarily for locomotion while driving and / or to cover the drive energy by another power source in order to cover the range of the electric vehicle to increase. For this purpose, a range extender typically includes an internal combustion engine and an electric generator coupled to the internal combustion engine. The electrical power generated by the generator may then be used to charge the traction accumulator or power the electric traction machine of the electric vehicle. Moreover, it is also conceivable that the internal combustion engine without the detour via the electric generator with the drive shaft of the motor vehicle can be coupled.

Instead of an internal combustion engine-generator system, a fuel cell can be used as a range extender, which provides additional electrical energy to drive the vehicle.

Typically, the range extender is started depending on certain parameters detected at the respective current time, in particular when a lower charge state threshold (SoC) of the traction memory is reached,

The early start of the range extender is often undesirable in terms of energy and comfort, since the efficiency of the range extender is lower and the operation of the range extender is associated with vehicle vibrations and a higher noise level. The range extender, however, prevents the traction memory from taking a long break and reduces the choice of destination due to the traction memory's limited range.

If the start of the range extender is only dependent on vehicle parameters currently recorded, such as reaching a lower SoC threshold, this will cause the range extender to tend to switch on too early. In addition, the range extender in this case is often dimensioned large enough to handle any type of track with a minimum requirement of drive dynamics (maximum speed, acceleration) can.

In detail, the disadvantages discussed below result:
The capacity of the energetically efficient, primary charge storage station loaded primary traction memory is not fully utilized because the discharge of the traction memory is terminated too early with the addition of the range extender or at least reduced.

The range extender is used more frequently than it would actually be required, which reduces ride comfort, for example, through higher noise levels and vehicle vibration when operating the range extender. In addition, conventional operating strategies for a range extender do not take into account comfort limitations (for example due to acoustics or vibrations).

The vehicle is made heavier and more expensive by a range extender that is sized to handle all the required maneuvers, for example, with a sizing that only covers a maximum continuous speed in the plane.

When the traction accumulator is empty, the vehicle offers only low drive dynamics on longer inclines and / or at high speeds, since the power delivered by the range extender is low.

In addition, the range extender may be engaged in unfavorable links (for example, in a lane or in a non-driving zone for internal combustion engines); a connection or disconnection of the range extender taking into account special sections is not provided.

From the publication US 5,778,326 is a navigation-based charging method for the battery of a hybrid vehicle known. In this case, depending on navigation information, a statement is made about the battery charge that is necessary to reach the destination. Besides, this is out of this Reference is known to increase the charge of the battery to nearly 100% before a hill slope is reached.

From the publication US 2007/0294026 A1 For example, a navigation-based operating method for a hybrid vehicle is known in which the battery is charged by using the internal combustion engine as a drive before reaching an engine driving prohibition zone.

In the publication US 2007/0208467 A1 The engine of a hybrid vehicle is used to ensure that the battery does not empty before reaching the destination. It also determines when the battery is being charged.

From the publication FR 2811268 A1 It is known to use information (eg, slope, average speed) of a navigation system to control the operation of an internal combustion engine of a hybrid vehicle.

It is an object of the invention to provide a method for operating a range extender in an electric vehicle with an electric traction memory. Here, the activation time of the range extender should be chosen favorably.

The object is solved by the features of the independent claims.

The invention relates to the operation of a range extender in an electric vehicle, in particular in an electric car, with an electric traction storage (for example, lithium-ion battery). The range extender preferably comprises an internal combustion engine and an electric generator coupled to the internal combustion engine. The power of the range extender may be useful for charging the electric traction memory. Alternatively or additionally, it can be provided that the power of the range extender for driving the electric vehicle can be used.

The invention is a predictive (predicative) operating strategy of the range extender. In this case, the invention preferably uses information of a navigation device, d. H. There is a link to a navigation device.

One aspect of the invention relates to a method of determining when or where the range extender is activated on a forward route. According to the method, a presumably required energy of the electric vehicle is calculated via preceding route sections up to a point of a determined travel route, in particular up to the destination point or a following electronic horizon of the system. The required energy can optionally already take into account the current state of charge of the traction memory and be reduced by the currently stored energy of the traction memory. The energy required is preferably calculated using information from a navigation system. The expected energy required can also be specified as the state of charge or the state of charge of the traction memory.

According to the method, it is determined when or where the range extender is activated. This takes place as a function of the energy that is expected to be required and taking into account the anticipated power or energy of the range extender on the route sections of the route ahead. Furthermore, the current state of charge of the traction memory and / or a predetermined minimum state of charge of the traction memory at the destination of the route or at another point of the route are preferably taken into account.

The power (energy) can refer to the charging power (charging energy) or the drive power (driving power) or to the sum of both. The anticipated power or energy of the range extender is preferably calculated using information (eg, length, speed, or slope information) of a navigation system.

Preferably, the activation of the range extender does not take place, if this is not necessary taking into account the expected energy and taking into account the expected power or energy of the range extender on the route sections of the route ahead and any other influencing factors (such as minimum charge at the destination).

To determine when or where the range extender is activated, a forward activation point (eg the time of activation or the time to activation, the waypoint of activation or a distance to activation) can be calculated in advance. For example, it can be calculated that the range extender should be activated in 20 minutes or 30 km, for example. The calculation of the activation point can be updated continuously, for example every n minutes, every n kilometers or during each route segment once.

Alternatively, it may be repeatedly (for example every n seconds or minutes, every n meter or kilometer or during each route segment once) to check whether the range extender should now be activated to determine when or where the range extender will be activated. If the exam is positive, an (immediate) activation of the range extender takes place.

The power or energy of the range extender is preferably described by route section related performance data or energy information on the preceding route sections. For example, each route section is assigned its own energy specification or performance specification. This can be charging power information or charging energy information. Alternatively or additionally, the route section related information may relate to the drive power or drive energy of the range extender.

• – dem Straßentyp des jeweiligen Routenabschnitts;
• – einer erwarteten Geschwindigkeit oder erlaubten Höchstgeschwindigkeit in dem jeweiligen Routenabschnitt;
• – einer Umwelt-Randbedingung, insbesondere die Zugehörigkeit des Routenabschnitts zu einer Umweltzone oder zu einer Zone mit ähnlichen lokal begrenzten Verbrennungskraftfahrzeugs-Betriebseinschränkungen oder zu einer Fahrverbotszone für Kraftfahrzeuge mit Verbrennungsmotoren;
• – der Wahrnehmbarkeit des Betriebs des Range-Extenders auf dem jeweiligen Routenabschnitt, insbesondere die akustische oder schwingungs- oder vibrationsverursachte Wahrnehmbarkeit des Betriebs des Range-Extenders auf dem jeweiligen Routenabschnitt; und/oder
• – der Lage des jeweiligen Routenabschnitts auf der vorausliegenden Route, insbesondere dem Abstand des Routensegments zum Ziel (beispielsweise sollte der Range-Extender in dem letzten Segment vor dem Ziel überhaupt nicht oder nur mit geringer Leistung betrieben werden, da die Wahrnehmbarkeit des Range-Extenders hier hoch ist).

Each route section related performance statement or energy information is preferably dependent on one or more properties, in particular the nature of the respective route section. The power specifications or energy specification of the range extender for the individual route sections depend, for example, on:

• - the road type of the respective route section;
• An expected speed or maximum speed in the respective route section;
• An environmental boundary condition, in particular the fact that the route section belongs to an environmental zone or to a zone with similar locally limited internal combustion engine operating restrictions or to a traffic prohibition zone for motor vehicles with internal combustion engines;
• The perceptibility of the operation of the range extender on the respective route section, in particular the audible or vibration or vibration-induced perceptibility of the operation of the range extender on the respective route section; and or
• - The location of each route section on the route ahead, in particular the distance of the route segment to the destination (for example, the range extender in the last segment in front of the target should not be operated at all or only with low power, since the visibility of the range extender here is high).

For example, the better the road type (eg highway) or the higher the speed on the particular route segment, the higher the performance of the range extender on that leg may be, since the range extender is less noticeable at higher speeds (e.g. B. About noise or vibration) is. Thus, the range extender can be operated at higher speeds with higher power, without the range extender is perceived by the driver as disturbing.

At low speeds or on low-speed road types (eg, game roads), it may be advantageous to operate the range extender at lower power or not at all, as the operation of the range extender is clearly perceptible here (e.g. a corresponding operating noise).

In addition, the range extender power for a leg of the route may depend on the route section's affiliation to an environmental zone (or zone with similar localized combustion vehicle operational limitations) or to a non-driving zone for automotive internal combustion engines. For example, for such a traffic prohibition zone, the charging power for the respective route section is assumed to be zero.

Preferably, a route section-related operating point (eg speed, torque) is respectively determined in dependence on the aforementioned boundary conditions. From the respective operating point, the respective route segment-related performance can then be determined.

The determination of an activation point can be effected, for example, by determining a route section in which the sum of the charge energy specifications of the range extender from the last route section to this route section exceeds the required energy by a certain amount (for example by a minimum SoC). This route section results in the optimal starting point of the rank extender. This is related to 3 and 4 will be explained later by way of example.

To determine when or where the range extender is activated, a route segment related energy quantity may be determined from the sum of the charge energy information of the last n route segments (calculated from the target point or the electronic horizon) and the energy required as negative weighted. The route segment-related energy quantity is then compared with a threshold value. This energy quantity can be determined for a plurality of route sections and thus the route section for which the energy quantity exceeds the threshold value can be determined. This route section results in the optimal starting point of the rank extender. This is related to 3 and 4 will be explained later by way of example.

Preferably, the energy that is expected to be required is estimated by the route section related energy values or power values (for example, the average expected drive power in the respective route section) for the ahead route sections are determined in particular using information from the navigation system. For example, a separate power value or energy value is assigned to each route section lying ahead to the destination point or electrical horizon. The energy that is expected to be required is then determined as a function of these section-related values, in particular from the sum of the section-related values.

The expected energy can already take into account the current state of charge, d. H. the required energy is, for example, the energy for reaching the target point or electric horizon reduced by the current energy (current state of charge) of the electric traction memory.

• – einer erwarteten Geschwindigkeit oder erlaubten Höchstgeschwindigkeit in dem jeweiligen Routenabschnitt,
• – der Länge des jeweiligen Routenabschnitts,
• – von Steigungsdaten oder Höhendaten des jeweiligen Routenabschnitts, oder
• – des Straßentyps des jeweiligen Routenabschnitts.

The section-related energy values or performance values can be determined as a function of one or more properties of the respective route section, in particular depending on

• An expected speed or maximum speed in the respective route section,
• - the length of the respective route section,
• - of slope data or elevation data of the respective route section, or
• - the road type of the respective route section.

In addition to the properties of the respective route section, however, the section-related energy value or power value can also be dependent on the driver type or the vehicle state.

The operating point of the range extender at the current time can be chosen in addition to vehicle parameters also depending on the data of the current route section, for example in a residential area or an environmental zone other than on a highway or overland route section, analogous to the operating point assumption for the range extender and thus likely Performance in the still ahead route sections.

The invention will be described below with reference to the accompanying drawings with reference to several embodiments. In these show:

1 shows an embodiment of a controller for controlling a range extender in an electric vehicle;

2 shows an exemplary profile of the instantaneous power demand over a route ahead;

3 shows an embodiment of a method for determining the activation point of a range extender; and

4 shows four diagrams illustrating a calculation example for the method described above.

1 shows an embodiment of a control unit 1 to control a range extender 2 in an electric vehicle, especially in an electric car. The range extender 2 includes an internal combustion engine 7 and an electric generator coupled thereto 8th , The electrical energy of the electric generator 8th will either charge an electric traction store 9 (For example, a lithium-ion battery) and / or for driving the electric drive machine 10 used. The control unit 1 uses a predicative operating strategy for controlling the range extender 2 , The operating strategy is preferably characterized by the fact that as much energy from the traction memory 9 is pulled before the range extender 2 is started. In addition, the operating strategy preferably takes into account the perceivable range extender for the driver and tries to keep it as low as possible by operating the range extender primarily there or operated there primarily with higher power where the engine of the range extender by the driver barely perceptible (eg at high speed on the highway).

In order to realize the predicative operating strategy, there is preferably a coupling with a navigation device present in the vehicle 3 which has access to map data. The navigation device 3 may be a fixed navigation device or a non-fixed accessory device. Furthermore, preferably existing internal vehicle data 4 for the predictive operating strategy of the range extender 2 used, this is preferably vehicle sensor data 4 (For example, driving speed, brake and accelerator pedal angle, vehicle settings via switches: sport, comfort, component temperatures), by the in-vehicle sensors 5 to be delivered.

The coupling can, depending on the nature of the navigation device via an internal vehicle bus system 6 (for example CAN, MOST or Flexray) or via an accessory interface 6 (for example, Bluetooth or USB) to accessories for information about this 11 from the navigation device 3 to the control unit 1 the operating strategy of the range extender 2 exchange. The information exchange preferably takes place continuously while driving and contains information 11 over the route sections ahead (ie those obtained from the map data Route segments) to the destination or to the electronic horizon. The information 11 For example, speed information (such as the expected speed and / or the maximum permitted speed in the preceding route sections), the slope information of the individual road sections, and road type information (highway, country road, etc.). About the interface 6 For example, a data record with a length or duration specification, a speed value, a road type specification (eg motorway, country road, etc.) and / or a slope value is transmitted per segment.

The choice of destination is made, for example, by direct input of the user; the route is then from the navigation device 3 certainly. Alternatively, the destination and the route may be automatically determined by a destination and route estimator.

Based on the information 11 can the controller 10 Estimate the amount of energy needed to reach the target or up to a trailing electric horizon. In addition, further information can be used to determine the energy.

• – die erwartete Geschwindigkeit (z. B. Durchschnittsgeschwindigkeit) oder erlaubte Höchstgeschwindigkeit in den vorausliegenden Routenabschnitten;
• – die einzelnen Längen dieser Routenabschnitte;
• – die einzelnen Steigungen dieser Routenabschnitte oder Höhendaten dieser Routenabschnitte;
• – die einzelnen Straßentypen der Routenabschnitte (Straße in einer Stadt, Spielstraße, Überlandstraße, Autobahn);
• – Gewicht, Roll- und/oder Luftwiderstand des Fahrzeugs;
• – den Wirkungsgrad des Antriebssystems in den Fahrsituationen, welche in den Routenabschnitten zu erwarten sind;
• – Informationen einer Fahrertyperkennung oder die Abschätzung der Fahrweise in zu erwartenden Fahrsituationen der vorausliegenden Routenabschnitte durch Verwendung fahrzeuginternen Größen (z. B. Geschwindigkeit oder Pedalstellung); und/oder
• – die Nutzung von Nebenverbraucher wie Heizung, Klimaanlage oder Licht.

The control unit 10 can estimate by one or more of the following information the amount of energy needed to reach the target:

• - the expected speed (eg average speed) or allowed maximum speed in the preceding route sections;
• - the individual lengths of these route sections;
• - the individual gradients of these route sections or elevation data of these route sections;
• - the individual road types of the route sections (street in a city, game road, overland road, motorway);
• - Weight, rolling and / or air resistance of the vehicle;
• The efficiency of the drive system in the driving situations to be expected in the route sections;
• Information of a driver type recognition or the estimation of the driving style in expected driving situations of the preceding route sections by using in-vehicle variables (eg speed or pedal position); and or
• - the use of secondary consumers such as heating, air conditioning or light.

Using the information described above or a portion of this information, a necessary energy demand can be estimated over the distance to the destination or to the electronic horizon. The energy demand determined in this way can already reflect the current state of charge of the traction memory 9 take into account and the currently available energy of the traction memory 9 be diminished.

Based on this energy demand and other information (in particular the expected performance or energy of the range extender 2 ) can be an operating strategy for the range extender 2 Specify, in particular, when or where the range extender 2 is activated. The operating strategy of the range extender 2 considers, in addition to the predicted energy demand over the route preferably the charging power or charging energy on the route sections lying ahead. Here, the interpretation of the range extender 2 regarding available power.

Optionally, the current state of charge of the traction memory 9 be considered (alternatively this is already included in the energy requirement).

Optionally, in the operating strategy, a minimum charging state specified by the user, in particular, may be taken into account at the destination or at another point of the route. If no minimum state of charge is specified, this is preferably assumed to be 0 (since this is the most energy-efficient).

In addition, in the operating strategy, the expected speed or the driving profile on the preceding route sections can be taken into account. From this one can in particular make a statement about the expected charging power of the range extender 2 derive on the preceding route sections (for example, the faster the speed, the faster it is loaded).

In addition, restrictions on the operation of the range extender can be derived in particular from the speed. These restrictions may involve a complete non-operation or only a limited operation (for example in a lower speed range). For example, it can be provided that at expected low speed and thus increased visibility of the range extender 2 (for example, via sounds or vibrations) of the range extender 2 is operated limited or not at all on the respective stretch of road.

Furthermore, the operating strategy may also include environmental boundary conditions such as environmental zones or similar locally limited combustion vehicle operational limitations or ( temporary / local) driving bans with internal combustion engine are considered. For example, it can be considered that on certain leading sections of the range extender 2 can not be operated and therefore in such sections no charging is possible and instead the energy from the traction memory 9 must be retrieved.

From the energy demand and one or more of the information described above, the time at which the range extender can be determined 2 is activated to the traction memory 9 support so that the destination is achieved safely and with the required drive dynamics and the existing charge in the traction memory 9 maximum is used. In addition, the best operating point of the range extender for the current driving situation can be determined from this.

The time can be calculated in advance (and updated ahead of time). Instead, the timing may be determined by continuously checking whether the range extender should now be started and what operating point (i.e., power) is necessary to cope with the remaining traction storage energy without significant limitations.

2 shows an exemplary profile of the current power requirement over a route ahead (here indicated in driving time). The energy demand to the target or to an electronic horizon results from summation or integration of the power requirement over the distance. The route is roughly divided into three areas: a city area 21 , a motorway area with slope 22 and another city area 23 , In the predicative operating strategy according to the invention, the prospective future energy requirement is taken into account. The control unit 1 recognizes while driving in the city area 1 the expected high future energy demand, especially during the motorway area 22 , and starts the range extender early 2 so that this the traction memory 9 invites. The range extender 2 then stays in operation. During the highway area 9 With high power requirements, the high power requirement on the previously loaded traction memory 9 and over the still active range extender 2 covered.

Based on 3 Now, an embodiment of a method for determining the activation point of the range extender 2 which is discussed in the control unit 1 is carried out.

From the navigation device 3 the preceding segments (ie route sections) 1 to x are known. The finer the segments are resolved, the more accurate the calculation of the optimal timing for the start of operation of the range extender 2 , Segment x describes the last segment before the target or in front of the electronic horizon.

According to step 100 out 3 The estimated drive energy required is estimated from the current route segment to the destination or electronic horizon. For this purpose, route section related drive power values P_Antr (i) with i = 1... X are used for the preceding route sections 1 to x to the destination or electronic horizon, and the expected required drive energy is determined as a function of the section-related power values P_Antr (i).

For example, the expected drive energy required to reach the destination or electronic horizon is determined as follows: E_Antr_Seg (1) = E_SoC_actual - P_Antr (1) · Δt (1) E_Antr_Seg (2) = E_Antr_Seg (1) - P_Antr (2) · Δt (2) ... E_Antr_Seg (x) = E_Antr_Seg (x - 1) - P_Antr (x) · Δt (x)

In this case, P_Antr (i) describe the mean expected drive power in the segment i and Δt (i) the estimated travel time in the segment i or the segment length of the segment i by the expected speed in the segment i. The size E_Antr_Seg (i) describes the required drive energy from the current segment to segment i. The energy quantity E_SoC_aktuell corresponding to the current state of charge is taken into account and only the required drive energy exceeding E_SoC_aktuell is specified. In the case of a drive energy actually required beyond the E_SOC_aktuell, the value E_Antr_Seg (i) is negative. The energy E_Antr_Seg (x) thus describes the required amount of energy to the target or electronic horizon.

The energy that is likely to be required can also be used as a state of charge or change in the charge state of the traction memory 9 be specified. In the case of an insufficient state of charge, for example, the state of charge SOC_Seg (x) at the destination point or electronic horizon is negative.

The segment-related power values P_Antr (i) are determined, for example, as a function of the property (for example road type or expected speed). In addition, the respective driver type and / or the vehicle condition and / or additional parameters are taken into account. For example, the power values P_Antr (i) are a function of the nature of the respective segment, the driver type and / or the vehicle state.

The required drive energy E_Antr_Seg (x) can be clearly negative. In this case, you come with the current battery charge without using the range extender 2 not the goal or electronic horizon.

If the stored energy - preferably taking into account a safety reserve - does not reach the destination (see step 101 ), becomes a starting point of the range extender 2 calculated on the track. This is the case, for example, when the energy E_Antr_Seg (x) is negative or, taking into account a safety reserve, falls below a negative limit. Alternatively, the calculation of the activation point of the range extender ends since, according to the current view, the range extender on the route does not have to be activated (the procedure in FIG 3 should, however, preferably be repeated during the course).

The starting point of the range extender 2 can be determined by determining the segment x - y in which the sum of the charge energies from the last segment x to this segment x - y exceeds the amount of energy E_Antr_Seg (x) by a certain amount (see step 102 ).

The starting point of the range extender can therefore be recalculated as follows, for example: E_Lade_Seg (x) = E_Antr_Seg (x) + P_Lade (x) · Δt (x) E_Lade_Seg (x - 1) = E_Lade_Seg (x) + P_Lade (x - 1) · Δt (x - 1) E_Lade_Seg (x - 2) = E_Lade_Seg (x - 1) + P_Lade (x - 2) · Δt (x - 2) ... E_Lade_Seg (x - y) = E_Lade_Seg (x - y + 1) + P_Lade (x - y) · Δt (x - y)

Here P_Lade (i) describes the charging power of the range extender 2 in the segment i. The variable P_Lade (i) is preferably a function of the properties of the segment i and preferably provides the desired optimum charging power of the range extender 2 From the customer's point of view here are, for example, the expected speed, presence of an environmental zone or similar locally limited combustion vehicle operating restrictions or a driving ban and / or the visibility of the range extender (eg via operating noise or vibration) on the respective segment i considered. The quantity E_Lade_Seg (i) is an energy quantity related to the segment i, which comprises the sum of the charge energies P_load (i) .DELTA.t (i) from the last segment to the segment i and the (negative) energy value E_Antr_Seg (x).

• (a) E_Lade_Seg(x – y) ≥ E_SoC_Min

The above calculation is performed up to the segment x - y, which defines the optimum start time of the range operation. For the segment x-y, the amount of charge energies from the last segment x up to this segment x-y the amount of energy E_Antr_Seg (x) by a certain amount (hereinafter described as E_SoC_Min, which, for example, the lowest safe storage State of charge limit for safe driving). The segment x - y is reached when

• (a) E_Lade_Seg (x - y) ≥ E_SoC_Min

• (b) E_Antr_Seg(x – y) ≥ E_SoC_Min

As an additional condition for the segment x - y, it is also preferable to:

• (b) E_Antr_Seg (x - y) ≥ E_SoC_Min

This means that the energy E_Antr_Seg (x-y) for this segment x-y has not become negative and remains greater than the threshold E_SoC_Min.

All of the calculations described above can be carried out in the same way instead of pure energy quantities even with equivalent state of charge quantities.

The expected starting point of the range extender 2 then corresponds to the beginning of the segment x - y.

In the case of x - y = 1 (i.e., current segment), the range extender should start immediately without checking condition (b).

4 illustrates in four diagrams a-d a calculation example of the method described above. In the first diagram a, the drive power P_Antr (i) for the individual segments 1 to 5 is plotted. The segment x = 5 is the last segment before the target or electronic horizon. For example, segments 1 and 2 are highway route segments, segment 3 is a highway route segment, segment 4 is an inner-city route segment, and segment 5 is a residential area segment. According to diagram a, the required drive power is greater in the highway segment 3 than in the highway plug segments 1, 2, which in turn require greater drive power than in the city segment 4 or in the residential area segment 5.

Diagram b shows the course of the required drive energy over the segments up to the target segment x = 5, the curve being from the current energy state E_SoC_actual of the traction memory 9 starts and is successively reduced by the drive energies P_Antr (i) .DELTA.t (i). The amount of the negative energy value E_Antr_Seg (x = 5) indicates the total drive energy required to reach the target point or the electronic horizon. In this case, E_Antr_Seg (x = 5) is clearly negative, ie energy is needed by activating the range extender 2 is produced.

The diagram c shows the individual charging powers P_load (i) for the individual segments. The charging power took into account, for example, the anticipated speed within the respective segment and the associated acoustic restrictions. So is the range extender at low speed 2 clearly perceptible than at high speed, so that at low speed, the charging power P_Lade (i) is chosen to be lower. In the residential area segment 5, the charging power P_Lade (5) is zero or very low, since the range extender 5 would be very clearly audible here. In addition, the charging power may take into account environmental conditions, such as the presence of an environmental zone or similar localized internal combustion engine operating restriction or a non-driving zone for internal combustion engines, in which case the charging power is reduced or entirely zero (in the case of a no-driving zone).

The last diagram d shows the recalculation based on the energy E_Antr_Seg (x = 5) at the target or the electric horizon to determine the starting point of the range extender 2 , Starting from the required energy E_Antr_Seg (x = 5) at the end of the segment 5, the estimated charging energy P_Lade (i) .DELTA.t (i) is successively added up in the individual segments. The addition starts in the last segment and takes place backwards (ie contrary to the direction of travel). As soon as an energy value E_Lade_Seg (x - y) is greater than the lower limit E_SoC_Min (here at x - y = 2), the segment x - y is reached, from which the range extender 2 should be started. In the case of diagram d, the range extender should be 2 starting at the beginning of segment 2.

• – Der Range-Extender kann möglichst klein dimensioniert werden. Durch die vorausschauende Betriebsstrategie kann die in dem Traktionsspeicher gespeicherte Energie und die vom Range-Extender gelieferte Leistung optimal kombiniert werden.
• – Die Ladung des Traktionsspeichers wird maximal genutzt. Durch die vorausschauende Betriebsstrategie wird der Betrieb des Range-Extenders verhindert, wenn die verbleibende Ladung zum Erreichen des Zieles – wenn auch knapp und unter optionaler Berücksichtigung einer Sicherheitsreserve – reicht und die je nach Strecke geforderte Antriebsdynamik durch den Traktionsspeicher abgedeckt ist. Hierbei ist zu berücksichtigten, dass der Traktionsspeicher außerdem mit zunehmender Entladung an Leistung verliert.
• – Streckenabschnitte, die einem Elektrofahrzeug hohe Leistung für eine bestimmte Zeit abverlangen (z. B. Autobahnabschnitte mit längerer Steigung oder Passstraßen) können mit höherer Dynamik befahren werden, da der Range-Extender-Betrieb entsprechend frühzeitig oder ortsgenau angepasst werden kann.
• – Der Betriebspunkt des Range-Extenders kann für die gesamte Fahrstrecke, den Fahrertyp und die aktuelle Fahrsituation optimiert und auf die Umwelt- und gesetzlichen Randbedingungen angepasst werden.

The invention described above deals with a predictive operating strategy for a range extender. The invention has, inter alia, the following advantages:

• - The range extender can be dimensioned as small as possible. The predictive operating strategy optimally combines the energy stored in the traction memory and the power delivered by the range extender.
• - The charge of the traction memory is used to the maximum. The predictive operating strategy prevents operation of the Range Extender when the remaining load reaches the target - albeit in short supply and with the optional consideration of a safety margin - and the required drive dynamics are covered by the traction accumulator. It should be noted that the traction memory also loses power with increasing discharge.
• - Lines that require a high-performance electric vehicle for a certain period of time (eg motorway sections with longer incline or mountain passes) can be driven with greater dynamics, since the range extender operation can be adjusted accordingly early or locally.
• - The operating point of the range extender can be optimized for the entire route, the driver type and the current driving situation and adapted to the environmental and legal boundary conditions.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 5778326 [0013]
• US 2007/0294026 A1 [0014]
• US 2007/0208467 A1 [0015]
• FR 2811268 A1 [0016]

Claims (16)

Method for operating a range extender ( 2 ) in an electric vehicle with an electric traction accumulator ( 9 ), whereby the performance of the range extender ( 2 ) for charging the electric traction memory ( 9 ) and / or for driving the electric vehicle, comprising the steps of: estimating a presumably required energy (E_Antr_Seg (x = 5)) of the electric vehicle via route sections lying ahead to a point of a determined travel route; and - specify when or where the range extender ( 2 ) is activated, depending on the expected energy required (E_Antr_Seg (x = 5)) and taking into account the anticipated power or energy of the range extender on the route sections of the route ahead. The method of claim 1, wherein the point of the forward travel route is a destination point or an electronic horizon. Method according to one of the preceding claims, wherein the power or energy of the range extender ( 2 ) is described by route section related performance information or energy information on the route sections lying ahead. The method of claim 3, wherein the route section related performance indications or energy information comprise route segment related charging performance data or charging energy information, and the step of determining when or where the range extender (s) 2 ) is activated, comprising: determining a route section in which the sum of the charge energy information from the last route section to this route section exceeds the required energy by a certain amount. The method of any one of claims 3-4, wherein the route section related performance indications or energy indications include route segment related charging power information or charging energy information and for determining when or where the range extender is activated comprises a route segment related energy quantity (E_Lade_Seg (x-3 = 2)) the sum of the charge energy information from the last route segment to the respective route segment and the energy required as negative weighting is determined and the route segment-related energy quantity (E_Lade_Seg (x-3 = 2)) is compared with a threshold value. Method according to one of claims 3-5, wherein a route section related power specification or energy output of the range extender depends on: - the road type of the respective route section; An expected speed or maximum speed in the respective route section; - an environmental boundary condition, in particular the fact that the route section belongs to an environmental zone or a zone with a local limited internal combustion engine operating restriction or to a traffic prohibition zone for motor vehicles with internal combustion engines; - the perceptibility of the operation of the range extender ( 2 ) on the respective route section, in particular the acoustic or vibration or vibration-induced perceptibility of the operation of the range extender ( 2 ) on the respective route section; and / or - the location of the respective route section on the route ahead. Method according to one of the preceding claims, wherein a route section related operating point is determined depending on: - the road type of the respective route section; An expected speed or maximum speed in the respective route section; - an environmental boundary condition, in particular the fact that the route section belongs to an environmental zone or a zone with a local limited internal combustion engine operating restriction or to a traffic prohibition zone for motor vehicles with internal combustion engines; - the perceptibility of the operation of the range extender ( 2 ) on the respective route section, in particular the acoustic or vibration or vibration-induced perceptibility of the operation of the range extender ( 2 ) on the respective route section; and / or - the location of the respective route section on the route ahead. Method according to one of the preceding claims, wherein the step of determining when or where the range extender ( 2 ) is activated, - by determining a forward activation point, or - by repeatedly checking whether the range extender is to be activated. Method according to one of the preceding claims, wherein the range extender ( 2 ) an internal combustion engine ( 7 ) and an electric generator coupled to the internal combustion engine ( 8th ). Method according to one of the preceding claims, wherein the method contains information of a navigation device ( 3 ) uses. Method according to one of the preceding claims, wherein the step of estimating the expected energy required (E_Antr_Seg (x = 5)) comprises: Determining or retrieving a route section of related energy values or power values for the preceding route sections at least up to the point on the determined travel route and estimating the expected required energy as a function of the section-related energy values or performance values for the preceding route sections. The method according to claim 11, wherein the section-related energy values or performance values are determined as a function of one or more properties of the respective route section, in particular as a function An expected speed or maximum speed in the respective route section, - the length of the respective route section, - of slope data or altitude data of the respective route section, and / or - the road type of the respective route section. Method according to one of the preceding claims, wherein the energy which is expected to be required depends on the current state of charge of the traction memory ( 9 ) is determined. Method according to one of the preceding claims, wherein the energy which is expected to be required (E_Antr_Seg (x = 5)) is determined as a function of one or more of the following influencing factors: - the expected speed or allowed maximum speed in the preceding sections of the route; - the individual lengths of the route sections ahead; Slope data or altitude data of the preceding route sections; - the road type of the route sections ahead; - Weight, rolling and / or air resistance of the vehicle; - the efficiency of the propulsion system in the preceding route sections; - the driving style or the driver type; and - the use of secondary consumers. A method according to any one of the preceding claims, wherein the step of determining when or where the range extender is activated is dependent on one or more of the following factors: - the current state of charge of the traction memory; A predetermined minimum state of charge of the traction memory at the destination of the route or at a point of the route; - the expected speed or allowed maximum speed on the route sections ahead; - the perceptibility of the operation of the range extender ( 2 ) on the individual route sections lying ahead, in particular the variable audible or vibration-induced perceptibility of the operation of the range extender ( 2 ) on the individual route sections ahead; and / or - environmental boundary conditions on the preceding route sections, such as environmental zones or zones with locally limited combustion vehicle operating restrictions or driving restrictions for motor vehicles with internal combustion engines. Control unit ( 1 ) for a range extender ( 2 ) in an electric vehicle with an electric traction accumulator ( 9 ), whereby the performance of the range extender ( 2 ) for charging the electric traction memory ( 9 ) and / or for driving the electric vehicle is usable, wherein the control unit ( 1 ) is arranged to carry out the method according to one of the preceding claims.

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